Many people in modem society spend extended amounts of time seated at work, school, home, and/or while traveling. Millions of people sit during lengthy commutes to and from work. Once at work, they sit continuously in an office chair for numerous hours. Additionally, many occupations require spending much of the day seated in an automobile. For example police officers, truck drivers, and taxi cab drivers, have jobs that require spending much of the day seated in an automobile. Similarly, airplane pilots spend much of the day seated in airplane seats.
For the most part, seats have several elements in common. They have a bottom portion, or seat pan, which receives the bulk of a user's weight, and a seatback, against which a user reclines. As relates to the seatback, a wide variety of mechanisms have been developed that purportedly provide back support for a user. Nevertheless millions of people continue to suffer from chronic and severe back pain caused by sitting for extended amounts of time. This is because conventional seatbacks have yet to provide back support that proactively resolve the medical causes of back pain, rather than the symptoms of back pain.
By way of background, the spine has four regions: cervical (neck), thoracic (upper back), lumbar (lower back), and sacral (tail bone). The sacrum is a large triangular fusion of five vertebrae that forms the base of the spine. The sacrum is located between the pelvic bones, which include the left and right ilium. The ilia each have a posterior border portion known as the posterior superior iliac spine (“PSIS”). The lumbar region includes the five vertebrae located above the sacrum, the thoracic region includes the twelve vertebrae located above the lumbar region, and the cervical region includes the seven vertebrae located above the thoracic region. Each region of the spine transitions into the adjacent region(s). For example, there is a thoracic-lumbar transition extending between thoracic vertebra 12(T12) and lumbar vertebra 1(L1).
As viewed from the side, the spine of a person with good posture forms a rearward curve known as the thoracic or kyphotic curve, and two forward projecting curves known as the lumbar or lordotic curve and the cervical curve. When taken together, these three curves form an S-shaped portion of the spine. This S-shape provides a great deal of strength, stability, flexibility, and endurance because the body primarily relies on the skeletal structures (i.e., the vertebrae) to support the weight of a persons body, rather than primarily relying on the musculature for support.
Relating to a user's posture, conventional seats have a number of shortcomings. First, conventional seats cause a user's spine to collapse from an S-shape into a C-shape. This collapse occurs because of improper back support. Stated differently, conventional seats lack strategically located support. Without strategically located support, the sacrum tilts rearward, and causes the spine to assume a C-shape. When the spine is in a C-shape, the user primarily relies on the musculature for support rather than skeletal structures. Sitting with the spine in a C-shape and over-relying on the musculature for support can lead to a number of immediate problems, for example, increased fatigue, increased pressure on the lumbar discs, or the creation of muscle stresses, strains, and spasms. Moreover, various long-term problems can also occur. These problems include pain in the lower back muscles, discomfort between the shoulder blades, tightening of neck muscles and muscle soreness and headaches.
A second problem is that conventional seats lack a contoured surface match between the surface of the seat and the surface of a user's anatomy. For example, conventional seats lack a proper nesting or receiving portion for the PSIS. In particular, the seat back pressures the PSIS. This can lead to poor posture, which often results in varying degrees of discomfort and back or spine problems. Forth, conventional seats provide poor distribution of the load forces experienced by the user.
Somewhat recently, it has been recognized that a spinal support device for applying a directed and concentrated force on the sacrum to properly position the pelvis and spine of a user could be constructed. In U.S. Pat. No. 6,125,851 (“the '851 patent”), a spinal support device is disclosed that helps support the sacrum of a user to induce the spine to take the preferable shape found in a normal standing posture.
While the '851 patent in part addresses the void created by seats around the sacral region, there still exists an urgent need to implement proper sacral support integrated within seatbacks, such as those used in residential seating, office seating, and/or vehicular seating. In particular, there exists a need to provide proper sacral support in a system that is integral to a seatback and adjusts according to the preferences of a variety of users that differ from each other in proportion and size. In addition, there exists a need to provide improved load distribution across the surrounding pelvic area, especially around the PSIS.
A full support system is also urgently needed, including proper primary sacral support combined with secondary or complementary support for other regions of the spine. Moreover, proper sacral support is urgently needed by persons that have obstructions between their backs and the seatbacks. For example, police officers often wear a belt with a handcuff wallet. The handcuff wallet forms a bulge or obstruction that makes sitting with good posture particularly difficult. Similarly, military personnel wear various body armors, and construction workers often wear bulky tool belts that can cause the spine to shift out of proper alignment when the worker is in a seated position.